Sorry if this seems even more nitpicky; I spent about a year in grad school thinking I wanted to do monetary theory for the rest of my life, and the main thing I got out of it was that "intrinsic value" is a bad concept that runs cover for muddy thinking and ultimately confuses everyone much more.
> Food provides value in that you can eat it to survive.
People value food (in many cases) because they can eat it. It doesn't mean that the value is intrinsic to the food. In fact, in many cases the value of the food is zero (or even negative! -- it still needs to be disposed-of) because no one wants it.
> Housing provides value in that it provides shelter from the elements.
People value housing for that reason, but housing doesn't have that value on its own. It has value because people want to use it for something. There are many abandoned houses that show this value is not inherent, but rather conditional and context-dependent (like all other value).
> A goat provides milk and you can eat it.
Yes, some people value goats for that reason. If you put one in my house, it will immediately have negative value, because not only do I not want it, the time it will take me to find a good way to get rid of it will dwarf the amount I can sell it for.
> Historically, people also used things like salt, which had intrinsic value (for preserving and flavoring food)
Again, people value it for that reason, but the value isn't in the thing (intrinsic). The value is imputed to the salt by people.
> Eventually you transition to precious metals, which also have some intrinsic value (for engineering various goods)
Again, no, but this one is perhaps the easiest to understand -- the value is imputed by people because of what they can do with it. In situations where they can't do anything with it, it has no value, revealing that the value was never intrinsic in the first place.
> The idea of having a currency completed untethered to anything of value is relatively new.
I would argue that this is not the case, and comes from a narrow way of looking at value. Say I'm a nerd (this may or may not be a true story). In early 2012, I find out about a thing called Bitcoin. I don't understand it very well, but it sounds cool, and I mine some just to say I have it, and then tell people I have it. I value it. I can't do anything with it physically, but that's true of a lot of things. I own a number of pieces of art that I value, even though I can't really do anything with them other than know they're there, sitting in my closet or storage unit. It doesn't make the value somehow not-real, because all value (in this sense of the word) is imputed to things by people; it's not in the things themselves.